Bacterial expression systems designed to produce large amounts of proteins for medical, industrial or research use are staples in the repertoire of recombinant DNA technology. One requirement is that the protein be easily purified and in as active a form as possible. It is proposed to use a cloned recombinant enzyme as a means to maximize the yield of biologically active proteins that can be obtained from bacterial expression systems. Experiments will be performed on test recombinant proteins in order to see if the yield of biologically active native molecules can be increased.